Changing Manual Tranny Oil to Cure Grinding

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sailorbob74133

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I have a 99 Nissan Almera which occasionally grinds / doesn't engage when I try and put it into fifth gear.

I was talking to someone about changing the gear oil since I'm going to replace the cv boots. The Hayens manual says my tranny takes Hypoid gear oil, viscosity SAE 80W to API GL4. This person recommended that I use Valvoline 75w-90 Limited Slip to help with the problem I'm having shifting into fifth gear.

According to the http://content.valvoline.com/pdf/synpower_gear.pdf product information sheet on Valvolines website it meets GL4,GL5 and MT1 ( whatever those are ).

What is this "limited slip" thing they are talking about and might it help my problem, as opposed to refilling with some cheaper oil like regular 75w-90 or 80w?
 
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Don't use the Valvoline limited slip stuff,it's for rear differentials. It'll make the shifting much worse and possibly destroy the synchros. Use a GL4 manual tranny oil only. I recommend Redline MT90.
 
Grinding into 5th is usually trouble. It's the least in need of synchronization because the engine speed is always on its way down into the "zone" that the trans will accept. Ie, never downshifting into 5th.

Honestly I'd find a used trans to put in while you're doing the CV joint work, at least it will save you some time.

Or try some miracle gear oil for a week to see if it stops the grinding. If it does, get a cheapo new clean drain pan from Dollar Tree (or local equivalent) and reuse your oil when you do the axle job.
 
I don't know about that one, but it is rare for a manufacturer to put heavy gear oil in a Japanese manual transmission. Most of them specify special MTF, 10W40 motor oil, or even ATF. Look up what Nissan says the Haynes manuals are often wrong.
 
You could always find a syncromesh fluid like Pennzoil or you could try Honda MTF.

Purely anecdotal, but my old VW transmission had a similar grind and required the same spec fluid. A change with Ravenöl 80 GL4 helped, but Honda MTF made it shift like butter again.
 
I would use a good GL-4 Manual transmission fluid such as

Redline MT-90 75W90 GL-4 Gear Oil

Dont use anything that says for limited slip as it wont have the right friction for your manual transmission.

Gear oil for limited slip rear end gears contains friction modifiers which are exactly the opposite of what you want in a manual transmission.
 
Originally Posted By: sailorbob74133
I have a 99 Nissan Almera which occasionally grinds / doesn't engage when I try and put it into fifth gear.

I was talking to someone about changing the gear oil since I'm going to replace the cv boots. The Hayens manual says my tranny takes Hypoid gear oil, viscosity SAE 80W to API GL4. This person recommended that I use Valvoline 75w-90 Limited Slip to help with the problem I'm having shifting into fifth gear.

According to the http://content.valvoline.com/pdf/synpower_gear.pdf product information sheet on Valvolines website it meets GL4,GL5 and MT1 ( whatever those are ).

What is this "limited slip" thing they are talking about and might it help my problem, as opposed to refilling with some cheaper oil like regular 75w-90 or 80w?


To help a synchronizer that's having difficulty holding, you want the OPPOSITE of "limited slip" additive. LS additive helps prevent the limited-slip clutches from "grabbing" as they approach lock-up, but you WANT a synchro to grab quickly. Under NO circumstances would I put limited-slip additive in any manual transmission.

The fact that this is a front-drive with hypoid gears sharing the same sump as the transmission pretty much screws you. If it didn't have the hypoid requirement, you could use something like Redline MT-85 with a friction package optimized for synchronizers, or even 40-weight engine oil (Jeep's recommended substitute for GL-3/4 gear oil in the old AX-15 transmission, and I can attest to the fact it works great in that application). But with that hypoid requirement, you're going to have to search and dig for the least friction-modified hypoid gear oil you can find, and I really doubt it will help at all.


Re-reading the original post there are some seeming conflicts- you say it "requires hypoid gear oil" but also "up to GL-4." Maybe there's a hypoid rated GL-4 out there, but most of the hypoid-rated lubes I know of are GL-5. If all it really takes is GL-4, then go with Redline MT-85 or MT-90. You could always contact Redline and see what they recommend, too.
 
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Yes this. I've used Redline in the trans on my Eclipse which requires GL4 and it made things much smoother. It wasn't transmission rebuild in a bottle but it helped. Don't use any GL5 in the transmission where a GL4 is listed as the fill. I've heard issues with GL5 attacking brass synchros or something along those lines.


Originally Posted By: Rand
I would use a good GL-4 Manual transmission fluid such as

Redline MT-90 75W90 GL-4 Gear Oil

Dont use anything that says for limited slip as it wont have the right friction for your manual transmission.

Gear oil for limited slip rear end gears contains friction modifiers which are exactly the opposite of what you want in a manual transmission.
 
Do NOT use a dual GL-4/GL-5 rated gear oil, it will be too slippery and interfere with synchronizer operation. Use a GL-4 ONLY gear oil such as Pennzoil Synchromesh-bet your shifting problems disappear! Not sure what's available in Israel, be safe out there.
 
I'm worried about the hypoid thing too, I checked on the red line website, but they only have american models. The American parallel to the Almera is the Sentra ( almost identical ) and for that car it says to use the MT90.
 
Originally Posted By: sailorbob74133
I'm worried about the hypoid thing too, I checked on the red line website, but they only have american models. The American parallel to the Almera is the Sentra ( almost identical ) and for that car it says to use the MT90.


^^This. You'll be amazed at how the MT90 will improve your shifting.
 
Originally Posted By: sailorbob74133
I'm worried about the hypoid thing too, I checked on the red line website, but they only have american models. The American parallel to the Almera is the Sentra ( almost identical ) and for that car it says to use the MT90.


I have been using Mt90 for a little over a year now and it works great even in cold weather. Last year I had to have the 6th gear syncro, bearing and the actual gear replaced because I had used O'Reilly 80w90 gear oil for about 3 years. It completely destroyed stuff in there. Made the switch to the proper lube and the tranny is as good as new.

I know better now and I'll make sure to use the correct lube from now on.
 
I'm not a mechanic, but you don't have to be one to give advice, but...Make sure that you shift bushing haven't worn out. I once pull parts for a 5 Sp Neon, I was going to swap out the 3sp Auto for the 5 speed manual and needed the floor shifter. From the donner car at the junkyard, I noticed the shift bushing at the Transmission side were bad, and also the bushings at the shifter were also bad. I always wondered if that is why the car ended up as junk, someone thought his trans was shot when it was only the bushings. Worth a look.
 
I can't see that this model has hypoid anything, it's small FWD. Despite the helical final drive and spider gears using the same oil I would suggest a thin GL4 oil like Redline MTL.
 
Honda MTF is probably the easiest to find alternative to a thin GL4. But unless you got the wrong fluid in it, putting a witches brew in is only a bandaid.
 
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Manual transmissions will use GL-4 over GL-5. A lot of GL-5 contains friction modifiers which can have negative impact on synchronizers.
 
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